1. Field of the Invention
A key type identification system for blood products.
2. Description of the Relevant Art
Human blood is xe2x80x9cTyped,xe2x80x9d or classified into groups, to determine its compatibility with blood or blood products from another individual. If incompatible blood or blood products are administered (as with a blood transfusion), the automatic blood cell- and tissue-destroying process which ensues can be disastrous, and potentially fatal to the recipient.
The current blood typing system is extremely sophisticated and complex, to the point that it can be difficult even for experienced health care professionals to comprehend or remember. Therefore, health care institutions engaged in the practice of transfusion medicine almost always utilize xe2x80x9cBlood Banks,xe2x80x9d or departments devoted exclusively to the maintenance, processing, typing, distribution, and documentation of all aspects of transfusion therapy.
While the compartmentalization of the blood bank is essential for safety and quality assurance, it often hides the technical aspects of transfusion therapy from health care personnel who are not directly involved with the Blood Bank. Although errors inevitably occur in blood processing, they are usually identified and corrected before the blood is administered. Nonetheless, the health care profession must continue to seek better safeguards and methods of avoiding the potentially fatal administration of incompatible blood products to a patient.
The current ABO typing system is complex and errors can occur anywhere in the processing of blood or blood products.
There are two parts or components of human blood which blood typing is based: the Red Blood Cells (RBC""s), and the Plasma. Red blood cells primarily carry oxygen to the tissues, and Plasma is the liquid medium through which they travel throughout the body.
On the surface of each RBC are xe2x80x9cAntigens,xe2x80x9d or proteins, which can react with xe2x80x9cAntibodies,xe2x80x9d found in the plasma. These Antigen-Antibody reactions usually result in the destruction of the RBC""s, and this process is an extension of one of the body""s natural methods of self defense. Blood xe2x80x9cTypingxe2x80x9d is a process which identifies the common or major Antigens and Antibodies found in blood. The three antigens are named xe2x80x9cA,xe2x80x9d xe2x80x9cB,xe2x80x9d an xe2x80x9cRHxe2x80x9d; the antibodies and are named for the antigens with which they combine: xe2x80x9cAnti-Axe2x80x9d, xe2x80x9cAnti-Bxe2x80x9d, and xe2x80x9cAnti-RH.xe2x80x9d Antigens are found on RBC""s, and Antibodies are fo und in Plasma.
When an antigen is combined with its corresponding Antibody, i.e., A with Anti-A, B with Anti-B, or RH with Anti-RH, a series of chemical reactions occur which ultimately destroy the RBC, and may trigger other tissue damaging processes. Humans have developed such that the genetically determined presence or absence of Antigens A, B, and RH determines the corresponding presence or absence of Anti-A, Anti-B, and Anti-RH.
In normal individuals, if A is found on the surface of the RBC, the plasma does not contain Anti-A; if A is not present on the surface of the RBC, the plasma does contain Anti-A. The same applies for B and RH. If both A and B are found on the surface, then neither Anti-A nor Anti-B are present in the plasma. If neither A nor B are present on the surface of the RBC, then both Anti-A and Anti-B are found in the plasma. The following Table B summarizes.
There are, by definition, combinations of blood types which will unite the antigen with its corresponding antibody, triggering the destruction of the RBC. For example, whole blood of type A positive (with RBC surface antigens A and RH, and plasma antibody Anti-B) when mixed with whole blood of type B positive (with RBC surface antigens B and RH and plasma antibody Anti-A) will bring together the RBC- destroying combinations of surface antigen A with plasma antibody Anti-A and surface antigen B with plasma antibody Anti-B. Thus, these types are considered xe2x80x9cincompatible.xe2x80x9d
A patient can only receive whole blood of the exact same type. This is called xe2x80x9ctype specificity.xe2x80x9d Because this limits the quantity of blood that is available to any given patient for transfusion therapy, whole blood collected from blood donors is usually fractionated or separated into its components to yield plasma, platelets and packed RBC""s.
The ABO typing system is also used to classify these individually separated blood components (i.e., Fresh Frozen Plasma, Platelets, and Packed RBC""s). The same compatibility rules apply, but the presence or absence of RBC""s (and their surface antigens) or plasma (and its antibodies) in the blood component determines its compatibility with a patient""s whole-blood. Packed RBC""s typically do not contain Plasma; therefore, the absence of plasma antibodies increases the number of combinations of blood types with which the Packed RBC""s are compatible.
A patient having blood type A positive, for example, while able to receive only whole blood of type A positive, could also receive Packed RBC""s of types A positive, A negative, O positive and O negative, and Plasma of types A positive and AB positive. Similarly, a patient of blood type B negative, while able to receive only whole blood of type B negative, could also receive Packed RBC""s of types B negative and O negative; and Plasma of types B negative, B positive, AB negative and AB positive. The following table summarizes whole blood types and their compatibility with individual blood components.
It is the shared responsibility of the blood bank and the individual health care practitioners to know and remember which blood mixture combinations are compatible, and to recognize and remember those combinations which are incompatible (and potentially lethal).
With any process, errors occur unavoidably. There are many areas in transfusion medicine into which human error can be introduced. Although regulations require that quality control measures and error identification and analysis programs be ongoing in health care facilities, the complete elimination of errors in collection, typing, labeling, distribution, administration, and documentation, can never be achieved. All attempts, therefore, must be focused on the minimization of certain types of easily avoidable errors.
While many safeguards are in place for the prevention of this potential catastrophe, there are still situations in which inadvertent administrations occur. For example, a unit of blood may have been sent to a different patient with the same name; the blood administrator may have confused one patient""s blood product for that of another patient. A wrong unit of blood may have been given under the stress of managing the patient""s life-threatening emergency, or during the late-night shift, or at any time when the administrator""s vigilance may be compromised.
Most patient-type and blood-product-type identification systems focus on the administrator""s verification of the accuracy of labeled information to assure type compatibility. Some inventions have attempted to invoke technology such as portable computers and bar-code readers to identify potential errors of type compatibility. Expensive computer technology is often unavailable, and humans process information with a fixed degree of fallibility, such that information is misprocessed by humans at a rate which is directly proportional to levels of stress.
Most patient-type and blood-product-type identification systems are human-driven; therefore, this invention is designed to simplify the recognition of type-compatibility and type-incompatibility to reduce the potential for the inadvertent administration of incompatible blood-products.
The invention embodies three dimensional complimentary and uncomplementary shapes to predict the theoretical compatibility and incompatibility of typed blood product combinations.
When a patient enters a health care setting in which blood transfusion therapy is possible, his/her blood type is determined. Next, a wrist identification band is applied with demographic information to which a labeled plastic tag is attached in the shape which corresponds to his/her whole-blood type according to the previously described model.
Once the need is determined for the administration of blood products, the blood bank affixes to the blood product packaging a labeled plastic tag which is in the shape of the blood type of the specific blood product according to the previously described model.
Once the blood product package is brought to the patient, and after existing protocols for proper identification of the patient and the corresponding blood product package, the two labeled plastic tags are compared. As previously described, complimentary shapes predict appropriately matched blood types, while uncomplimentary shapes warrant further verification.
The system is designed to be a simple, cost effective means of identifying Blood Type incompatibilities, and in confirming Blood Types compatibilities in blood transfusion therapy. Successful implementation of this model should improve patient safety in the health care setting.
Broadly the invention comprises a labeling system to ensure that blood products are compatible with a patient""s blood type. A blood product housing comprises a plurality of three-dimensional physical indicia corresponding to the antigen/antibody characteristics of a blood product. A patient housing comprises a plurality of mirror image three-dimensional physical indicia corresponding to the antigen/antibody characteristics of a blood product. The blood product housing is engaged to the patient housing. If the indicia mate and seat to one another this confirms that the blood product is compatible with that of the patient. If the indicia do not mate and seat to one another this confirms that the blood product is not compatible with that of the patient.
In a preferred embodiment, the indicia are block-like recesses and blocks which are arrayed to correspond to blood types.